This opinion piece is powered by my master credentials as the minor league recap guy. The primary criteria used to rank the players are actual game performance, in context with league level and league metrics. Secondary criteria include professional scouting reports, video and statistical analysis, intuition, and psychic powers.
While these lists try to rank the prospects from best to worst, I would more roughly divide this list into three groups: the first four, all 20-year-olds, all premium prospects, all on the same timeline; the next four, a little older, all exciting talents that have flashed their tools and have upside potential, and the last two, young and with the least track record. Rankings within the groups are somewhat superfluous.
age 20, primary level: High-A, 266/.376/.428